1. Field of the Invention
The present invention relates to apparatus for selectively supporting a bed section, and in particular to apparatus suitable for use with a hospital bed. More particularly, the present invention relates to apparatus for supporting a section of an articulated bed platform in a raised position such that the platform can be placed in a number of different positions.
2. Description of the Related Technology
Hospital beds often include an articulated platform comprising a number of separate sections which can be independently raised, thus enabling the platform to be arranged in a number of positions to suit the needs of the occupant and/or medical staff.
Typically, three sections are provided along the length of the platform; a backrest section which supports the occupant's upper body, a thigh section which supports the occupant's thighs (i.e. supports the occupant between the hips and the knees) and a calf section which supports the occupant below the knees. In a typical arrangement, a first end of the backrest section (that is the end adjacent the occupant's head) can be raised such that the occupant's torso can be supported with the occupant in a sitting position. The first end of the thigh section (that is the end disposed towards the head end of the bed) is pivotally attached to the bed frame at platform level and the second end of the thigh section (that is the end disposed towards the foot end of the bed) can be raised, such that the occupant's thighs can be supported when the occupant's legs are bent at the knee. The first end of the calf section is pivotally attached to the second end of the thigh section, and the second end of the calf section can be raised from the flat platform position.
When the second end of the thigh section and thus the first end of the calf section are in a raised position, and the second end of the calf section is not raised, both the occupant's thighs and calves are supported when the occupant's legs are bent at the knee. This is known as the Fowler position.
When the second end of the thigh section and thus the first end of the calf section are in a raised position, and the second end of the calf section is also in a raised position, both the occupant's thighs and calves are supported when the occupant's calves are raised and substantially parallel to the bed frame. This is known as the vascular position.
When the bed is arranged in the vascular position, a support mechanism is required to support the second end of the calf section in the raised position. Known designs of calf section supports include the use of two telescopic multi-position ratchet assemblies, one disposed generally along each long side of the bed. There are however disadvantages to this solution. First, the ratchet assemblies are not strong enough. This is partially because of the construction, but also because each ratchet assembly is not linked to the other, meaning that any load applied to one side of the bed is only carried by one of the ratchets. Second, when the thigh and calf sections of the bed are lowered to the flat platform position, the ratchet assemblies extend and lock so that when the thigh section is raised again the calf section is moved directly into the vascular position. This is disadvantageous when raising the occupant's legs into the vascular position is medically contra-indicated. Third, such ratchet assemblies are difficult to clean.
The present invention seeks to provide an improved mechanism for supporting a section of an articulated bed platform in a raised position.